1. Field of the Invention
The present invention relates to a luminescent device and a method of producing the same.
2. Description of the Related Art
Organic electroluminescence (organic EL) display devices, which are a self-emitting display device, are expected to be used in applications such as displaying or illumination. For instance, organic EL display devices have such advantages in display performances as higher visibility and less viewing-angle dependency, as compared with conventional displays such as CRTs or LCDs. Furthermore, organic EL displays have advantages in reducing the weight or thickness of the display. In addition to the above, organic EL display devices have a possibility of providing illuminating devices having a shape which has never been achieved by use of a flexible substrate.
Organic EL displays include a top-emission type display, which uses a color filter, and a bottom-emission type display. Top-emission type organic EL displays that do not have a color filter on an array-side substrate having an EL layer, as shown in FIG. 8, are typically produced by separately preparing units A and B having the following structure, and then bonding them with a sealing adhesive.
(A) Array-side substrate/thin film transistor (TFT; pixel)/flattening layer/metal electrode/electron transporting layer/EL luminescent layer (pixel)/hole transporting layer/transparent electrode/protective layer
(B) Seal-side substrate/color filter (pixel)
However, in the case where deformation of the array side substrate or the seal-side substrate occurs in the preparation process, the substrates tend to have a different degree of deformation. When the substrates have a different degree of deformation, positional alignment of pixels (positions indicated by “pixel” in the aforementioned (A) and (B)) that are formed on each substrate may be difficult. Occurrence of positional misalignment of the pixels may impair display characteristics such as color hue or resolution of the display, or may even damage the quality of the product.
As a method of forming pixels that form a color filter, in the cases of LCDs for instance) a method of producing pixels directly on an array-side substrate provided with a TFT by a photolithography method is known. In this method, for instance, a colored curable coating composition is applied on the array-side substrate, and development is conducted after exposing the coating to light. Accordingly, it is difficult to apply the photolithography method in the production of organic EL displays to form a color filter directly on an array-side substrate provided with an EL luminescent layer that tends to deteriorate due to moisture. If a protection is provided to cover the EL luminescent layer, the production process will become complicated and the cost will be increased.
Japanese Patent Application Laid-Open (JP-A) No. 2001-130141, for example, discloses a method of forming a luminescent layer or color filter by applying an organic material by an inkjet method to openings separated from each other by a pattern that has been formed by a transfer method using a donor sheet on a substrate onto which a pixel electrode or a luminescent layer is to be formed.
However, the above method intends to form a luminescent layer, or a color filter on a substrate on which a luminescent layer has not been formed. Therefore, when a color filter is formed after the luminescent layer has been formed, ink in the form of a liquid directly contacts the substrate on which the luminescent layer has been formed. Therefore, in order to avoid the deterioration of luminescent layer, the color filter needs to be formed on a separate substrate on which the luminescent layer is not formed.
The present invention has been made in view of the above circumstances, and intends to provide a luminescent device that can be produced at high yield and exhibit excellent display characteristics such as display color hue or resolution, and a method of producing a luminescent device in which degradation in display characteristics due to the positional misalignment of pixels can be suppressed while maintaining the production efficiency of the device.